I'm browsing 9gag for years. I see everything and I can opt out of topics.
On lemmy I have to actively subscribe to subs. That means I miss out on topics I'm not aware of. On pixelfed I also have to actively search for a tag. Same for mastodon.
How can I have a similar experience to 9gag (I am not speaking of the content. A lot of content is not what I am looking for. I refuse to make an account on 9gag but I'm fine wirh a fediverse account.
There should be an "all" tab or feed that you can go to on your platform - Mastodon has one, not sure about Pixelfed, and Lemmy has one too, that may give you the diversity that you're looking for?